Oils and lubricants are used for a variety of applications, including providing lubrication for engines and motors to extend lifetime and prevent failure. Oils that are used as lubricants provide lubrication between two moving surfaces, such as for example, bearings and other metal surfaces.
Drilling fluids (muds) are normally used in drilling oil and gas wells. These fluids are used to maintain pressure, cool drill bits, and lift, cuttings from the holes as the well is being drilled. Drilling fluids vary greatly in composition depending upon specific requirements of the well being drilled, as well as geological considerations.